From owner-svn-src-head@freebsd.org Wed Jul 8 14:30:47 2015 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 710E39965D2; Wed, 8 Jul 2015 14:30:47 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-ig0-x22f.google.com (mail-ig0-x22f.google.com [IPv6:2607:f8b0:4001:c05::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 36A08123D; Wed, 8 Jul 2015 14:30:47 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: by igrv9 with SMTP id v9so168371267igr.1; Wed, 08 Jul 2015 07:30:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=phJe2GIeiaiDO4+nnNxS6As8G5XgS6OkCay6xZYJjqc=; b=Jpij9rRaXo5SP+aCtyuWnC9ZBzKjrrlpFTlq48syielkAX1GKZOfmMtGDF3dCMMwyi zve2xPbexVDzzCLBtGOfMf3DuOhK7qOmsGz5idkafGBKcHoZX+V5glfPZg+iYXL6HdW7 Pv4TlkiUJ1sa/5ZdNytiiNQjzLTheszhAn83fwOZ/AYihntl5a16xvL83yDgBpV4Ao7Y kQRgpHBSKQ9ulo4/ryyUqpH7x2xePz48dfeUTMwtE6vSsTGFOC/FBuvoRrmDW3yOalCT 4vln1pdbr/ag5YASgB3IRettvzmWWd/PqefsCSLwPtYNfWYPmPDJQ/6+MBmqXhgHM9KL BwWg== MIME-Version: 1.0 X-Received: by 10.50.171.232 with SMTP id ax8mr19925850igc.32.1436365846576; Wed, 08 Jul 2015 07:30:46 -0700 (PDT) Received: by 10.36.38.133 with HTTP; Wed, 8 Jul 2015 07:30:46 -0700 (PDT) In-Reply-To: <201507081353.t68Dr0up028388@repo.freebsd.org> References: <201507081353.t68Dr0up028388@repo.freebsd.org> Date: Wed, 8 Jul 2015 07:30:46 -0700 Message-ID: Subject: Re: svn commit: r285270 - head/sys/sys From: Adrian Chadd To: Zbigniew Bodek Cc: "src-committers@freebsd.org" , "svn-src-all@freebsd.org" , "svn-src-head@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 08 Jul 2015 14:30:47 -0000 Why is this implemented in sys/sys/bus_dma.h, rather than in a machdep header? -a On 8 July 2015 at 06:53, Zbigniew Bodek wrote: > Author: zbb > Date: Wed Jul 8 13:52:59 2015 > New Revision: 285270 > URL: https://svnweb.freebsd.org/changeset/base/285270 > > Log: > Add memory barrier to bus_dmamap_sync() > > On platforms which are fully IO-coherent, the map might be null. > We need to guarantee that all data is observable after the > sync operation is called. Add a memory barrier to ensure that on ARM. > > Reviewed by: andrew, kib > Obtained from: Semihalf > Sponsored by: The FreeBSD Foundation > Differential Revision: https://reviews.freebsd.org/D3012 > > Modified: > head/sys/sys/bus_dma.h > > Modified: head/sys/sys/bus_dma.h > ============================================================================== > --- head/sys/sys/bus_dma.h Wed Jul 8 13:19:13 2015 (r285269) > +++ head/sys/sys/bus_dma.h Wed Jul 8 13:52:59 2015 (r285270) > @@ -282,13 +282,25 @@ int bus_dmamem_alloc(bus_dma_tag_t dmat, > void bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map); > > /* > - * Perform a synchronization operation on the given map. > + * Perform a synchronization operation on the given map. If the map > + * is NULL we have a fully IO-coherent system. On every ARM architecture > + * there must be a memory barrier placed to ensure that all data > + * accesses are visible before going any further. > */ > void _bus_dmamap_sync(bus_dma_tag_t, bus_dmamap_t, bus_dmasync_op_t); > +#if defined(__arm__) > + #define __BUS_DMAMAP_SYNC_DEFAULT mb(); > +#elif defined(__aarch64__) > + #define __BUS_DMAMAP_SYNC_DEFAULT dmb(sy); > +#else > + #define __BUS_DMAMAP_SYNC_DEFAULT {} > +#endif > #define bus_dmamap_sync(dmat, dmamap, op) \ > do { \ > if ((dmamap) != NULL) \ > _bus_dmamap_sync(dmat, dmamap, op); \ > + else \ > + __BUS_DMAMAP_SYNC_DEFAULT \ > } while (0) > > /* >